A wiki is a collection of Web pages designed to enable anyone who accesses it to contribute or modify content, using a simplified markup language. The collaborative encyclopedia Wikipedia is one of the best-known wikis.

Editing wiki pages

Ordinarily, the structure and formatting of wiki pages are specified with a simplified markup language, sometimes known as "wikitext". For example, starting a line of text with an asterisk ("*") is often used to enter it in a bulleted list. The reason for taking this approach is that HTML, with its many cryptic tags, is not very legible, making it hard to edit. Wikis therefore favour plain text editing, with fewer and simpler conventions than HTML, for indicating style and structure.

Users can supply an "edit summary" when they edit a page. This is a short piece of text (usually one line) summarizing the changes. It is not inserted into the article, but is stored along with that revision of the page, allowing users to explain what has been done and why; this is similar to a log message when committing changes to a revision control system.

This wiki keep a record of changes made to wiki pages, and every version of the page is stored. This means that authors can revert to an older version of the page, should it be necessary because a mistake has been made or the page has been vandalized.